/SENSOR

Block Format Keyword

/SENSOR - Sensors

Description

Describes the sensors which are used to activate or deactivated an object according to the defined characteristics.

Format

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
/SENSOR/type/sens_ID/unit_ID
sens_title
Tdelay

Beside sensor type = TIME, additional cards are required if the following sensor types are used.

If Sensor Type = ACCE

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Nacc

If Nacc > 0: Define Nacc Accelerometer Reference

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accel_ID	Dir	min		Tmin

If Sensor Type = GAUGE

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Ngau

If Ngau > 0: Define Ngau Gauge Reference

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
gauge_ID		Pmin		Tmin

If Sensor Type = DIST

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
node_ID1	node_ID2	Dmin		Dmax

If Sensor Type = SENS, AND and OR

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sens_ID1	sens_ID2

If Sensor Type = NOT

(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)	(9)	(10)
sens_ID1

If Sensor Type = INTER

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int_ID	DIR	Fmin		Fmax		Tmin		Fcut

If Sensor Type = RWALL

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rwall_ID	DIR	Fmin		Fmax		Tmin

If Sensor Type = RBODY

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rbody_ID	DIR	Fmin		Fmax		Tmin

If Sensor Type = SECT

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sect_ID	DIR	Fmin		Fmax		Tmin

Field

Contents

SI Unit Example

type

Sensor type keyword

(see table below)

sens_ID

Sensor identifier

(Integer, maximum 10 digits)

unit_ID

Optional unit identifier

(Integer, maximum 10 digits)

sens_title

Sensor title

(Character, maximum 100 characters)

Tdelay

Time delay

(Real)

Nacc

Number of accelerometers (Nacc < 6)

(Integer)

Ngau

Number of gauges (Ngau < 6)

(Integer)

accel_ID

Accelerometer identifier

(Integer)

gauge_ID

Gauge identifier

(Integer)

Dir

Direction (Comment 7)

(Text)

min

Minimum absolute value of acceleration

(Real)

Pmin

Minimum absolute value of pressure

(Real)

Tmin

Minimum time duration before activation when criteria is reached (Comment 7 and Comments 15 through 18)

(Real)

node_ID1

Node identifier 1

(Integer)

node_ID2

Node identifier 2

(Integer)

Dmin

Distance minimum

(Real)

Dmax

Distance maximum

(Real)

sens_ID1

Activation sensor identifier IS1

(Integer)

sens_ID2

Deactivation sensor identifier IS2

(Integer)

int_ID

Interface or sub-interface identification number

(Integer)

DIR

Force direction (Comments 15 through 18)

If Type = INTER

•	DIR =NF (Normal Force)

•	DIR =TF (Tangent Force)

If Type = RWALL

•	DIR =NF (Normal Force)

•	DIR =TF (Tangent Force)

•	DIR =X (Force in X direction)

•	DIR =Y (Force in Y direction)

•	DIR =Z (Force in Z direction)

If Type = RBODY

•	DIR =TF (Total Force)

•	DIR =TM (Total Moment)

If Type = SECT

•	DIR =TF (Total Force)

•	DIR =TM (Total Moment)

•	DIR =FN (Normal Force)

•	DIR =FT (Tangent Force)

•	DIR =FX (Force in X direction)

•	DIR =FY (Force in Y direction)

•	DIR =FZ (Force in Z direction)

•	DIR =MX (Moment in X direction)

•	DIR =MY (Moment in Y direction)

•	DIR =MZ (Moment in Z direction)

(Integer)

rwall_ID

Rigid wall identification number

(Integer)

rbody_ID

Rigid body identifier

(Integer, maximum 10 digits)

sect_ID

Section identifier

(Integer, maximum 10 digits)

Fmin

Minimum force

Default = 0 (Real, maximum 20 fields)

Fmax

Maximum force

Default = 0 (Real, maximum 20 fields)

Fcut

Cutoff frequency (Comment 19)

≠ 0: a 4-pole Butterworth filter is used.

(Real)

Type	Description
TYPE0, TIME	Start time
TYPE1, ACCE	Accelerometer
TYPE2, DIST	Nodal distance
TYPE3, SENS	Activation with sens_ID1 Deactivation with sens_ID2
TYPE4, AND	ON when sensors sens_ID1 AND sens_ID2 are ON
TYPE5, OR	ON when sensors sens_ID1 OR sens_ID2 are ON
TYPE6, INTER	Activation/Deactivation of sensor by interface contact
TYPE7, RWALL	Activation/Deactivation of sensor by contact with rigid wall
TYPE8, NOT	ON when sens_ID1 is OFF
TYPE10, GAUGE	Pressure gauge
TYPE11, RBODY	Activation of sensor by Rigid Body force criteria
TYPE12, SECT	Activation of sensor by Section force criteria
USER1, USER2, USER3	user’s sensor

1.	The sensor types AND, OR, NOT, INTER, RWALL, RBODY and SECT work with all options using sensors.

2.	USER1, USER2 and USER3 are sensors that you may create.

The input format must be defined by a user supplied program. Contact Altair Development France for assistance with programming user sensors.

3.	Sensors can be used to activate airbags, imposed forces, pressures, and fixed velocities.

4.	Sensors can be used to activate or deactivate these elements: brick, quad, shell, truss, beam, spring or 3N Shell with /ACTIV.

5.	A sensor can only be activated once.

6.	For Sensor type TIME, the sensor is activated after the time delay Tdelay.

7.	For Sensor type ACCE:

•	Sensor is activated (at Tsensor) if one of the accelerometers gives an acceleration greater than min during a time greater than Tmin:

Tsensor = Tdelay + Tmin

with, Tmin (time when the criteria is reached).

•	Dir defines the acceleration direction:

= X: X direction

= Y: Y direction

= Z: Z direction

= XY: XY plane

= YZ: YZ plane

= ZX: ZX plane

= XYZ: total acceleration

8.	For Sensor type DIST:

•	Nodal distance node_ID node_ID2 is defined as: Dmin < \| node_ID node_ID2 \| < Dmax.

•	If Dmax is reached in traction (\| node_ID node_ID2 \| > Dmax) or Dmin is reached in compression (\| node_ID node_ID2 \| < Dmin) at time Treach, the sensor is then activated at time Tsensor:

Tsensor = Tdelay + Treach

9.	For Sensor types SENS, AND, OR:

•	The sensor is activated after activation of sensor sens_ID1.

•	Minimum activation duration is given by Tdelay.

•	After Tdelay, sensor is deactivated if sens_ID2 is activated.

•	If sens_ID2 = 0, the sensor is deactivated after Tdelay.

10.	For Sensor type GAUGE:

•	Sensor is activated (at Tsensor) if one of the gauges gives a pressure greater than Pmin during a time greater than Tmin:

Tsensor = Tdelay + Tstart

•	Tstart: Time when pressure criterion is reached.

11.	For Sensor type SENS:

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12.	For Sensor type AND:

The sensor is activated one cycle after activation at the same time as sensor sens_ID1 and sens_ID2

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13.	For Sensor type OR:

The sensor is activated one cycle after the activation of sensor sens_ID1 or after the activation of sens_ID2.

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14.	For Sensor type NOT:

The sensor is activated one cycle after deactivation of sens_ID1.

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15.	For Sensor type INTER

- A Sensor is activated when contact on interface is detected, and following force criteria is satisfied:

•	F_cont < Fmin or Fcont > Fmax during Tmin

Dir defines Force direction:

•	NF = Normal Force

•	TF = Tangent Force

•	Sensor is deactivated if the contact is lost

- If there is no impact during a time equal to Tdelay (Line 3), the sensor is deactivated.

- A sensor is used for one interface or sub-interface. You can use several sensors of type INTER.

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16.	For Sensor type RWALL:

- The sensor is activated one cycle after impact on the rigid wall.

- A sensor is used for one rigid wall. You can use several type RWALL sensors.

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- Sensor is activated when contact on rigid wall is detected, and following force criteria is satisfied:

•	F_cont < Fmin or Fcont > Fmax, during Tmin

Dir defines Force direction:

•	NF = Normal Force

•	TF = Tangent Force

•	X = Force in X direction

•	Y = Force in Y direction

•	Z = Force in Z direction

•	Sensor is deactivated if the contact is lost

17.	For Sensor type RBODY:

Sensor is activated when rigid body force satisfies the criteria:

•	F_cont < Fmin or Fcont > Fmax, during Tmin

Dir defines Force direction:

•	TF = Total Force

•	TM = Total Moment

18.	For Sensor type SECT:

Sensor is activated when section force satisfies the criteria:

•	F_cont < Fmin or Fcont > Fmax, during Tmin

Dir defines Force direction:

•	TF = Total Force

•	TM = Total Moment

•	FN = Normal Force

•	FT = Tangent Force

•	FX = Force in X direction

•	FY = Force in Y direction

•	FZ = Force in Z direction

•	MX = Moment in X direction

•	MY = Moment in Y direction

•	MZ = Moment in Z direction

19.	To obtain a class 1000 SAE filtering, the recommended value for Fcut is 1650 Hz (1.65 ms-1). Application of the filter helps to prevent wrong activation of the force based sensor, due to a local force peak. Another method to avoid this is to use a small value for Tmin.

20.	Values for force and moment component limits in the force based sensors (types RWALL, SECT) can be positive and negative. Normal, tangent, total force and moment values are always positive.

21. Tdelay is not applicable with the force based sensors type RWALL, INTER, RBODY, or SECT.